 [nondet]rdf_nth0(?Index, 
+RDFList, ?X)
[nondet]rdf_nth1(?Index, 
+RDFList, ?X)True when X is the Index-th element (0-based or 
1-based) of
RDFList. This predicate is deterministic if Index 
is given and the list has no multiple rdf:first or rdf:rest values.
[nondet]rdf_nth0(?Index, 
+RDFList, ?X)
[nondet]rdf_nth1(?Index, 
+RDFList, ?X)True when X is the Index-th element (0-based or 
1-based) of
RDFList. This predicate is deterministic if Index 
is given and the list has no multiple rdf:first or rdf:rest values.